This invention relates to an improved retaining wall construction and more particularly to a retaining wall construction generally of the type first disclosed in a series of Vidal patents including U.S. Pat. No. 3,421,326, U.S. Pat. No. 3,686,873, U.S. Pat. No. 4,045,965 and U.S. Pat. No. 4,116,010.
Vidal teaches that longitudinal, tensile members may be positioned within a granular, compacted mass of earth to thereby enhance the coherency of the particles which form the mass. The mass can then serve as a wall or embankment. This phenomenon of enhanced coherency is accomplished, at least in part, by frictional engagement of the particles in the mass with the tensile members extending through the mass.
Vidal teaches further that a particularly effective construction utilizes longitudinal metal strips as the tensile members. These longitudinal metal strips are arranged in a geometric array within a bulk form of compacted earth. To complete the construction the ends of at least some of the tensile members are affixed to facing panels so as to define the exposed facing or wall of the construction.
This general construction has found much acceptance particularly in the road building industry wherein such constructions are used as retaining walls for embankments and as roadway supports. Other uses of this construction technique include coal and grain slots, sea walls, bridge abutments and the like.
Subsequent to the aforesaid generic developments by Vidal, various species have been patented. For example, Hilfiker in U.S. Pat. No. 4,117,686 discloses the use of wire gridforms as a substitute for the tensile members developed by Vidal. Hilfiker has patented various wall constructions using wire gridform members in combination with various facing constructions. Hilfiker U.S. Pat. No. 4,117,686 discloses a wire grid facing construction in combination with a coarse rock backfill. Another Hilfiker patent shows that the wire grid facing member and grid tensile member may comprise a continuous member, U.S. Pat. No. 4,505,621. Later Hilfiker patents disclose the addition of a cast in place wall to the wire grid facing to further define the facing construction, Hilfiker U.S. Pat. Nos. 4,329,089, 4,391,557 and 4,643,618. Alternatively, Hilfiker discloses a precast facing construction in association with the gridform tensile members, U.S. Pat. No. 4,324,508.
There has remained, however, a generally unresolved problem which other constructions do not appear to adequately address. Specifically, when constructing an earth retaining wall of the type described, the granular material, which is compacted for cooperation with the tensile members, may not fully consolidate to its final volume during the period of wall construction. For example, compacted earth may consolidate approximately 90% of its expected bulk consolidation during the construction phase of such a retaining wall. Therefore, over time, the bulk form will continue to consolidate and as a result, this compacted mass of earth will impart straining forces on the planar front face of the bulk form. In the prior art constructions, the major portion of such strain was absorbed by the facing or wall construction generally associated with the bulk form embankment arrangement.
Where the facing or wall construction comprises a wire grid form, the distorting strain will not destroy the aesthetics of the facing construction. However, when a wire gridform facing construction is not desired, a solid facing construction, such as those suggested by the prior art, cannot accommodate such forces without adverse affect to their appearance.
Thus, there has remained a need for an improved construction for an earthen bulk form retaining wall construction and method for fabricating the same in which the reinforced earth bulk form can accommodate continued consolidation without affect to the facing or wall construction. The present invention comprises such an improved construction and method.